Six lines of research investigate (a) selective perception (what aspects of complex social stimuli get noticed) and (b) the direction taken by the ensuing stream of thought. A first set of studies predicts that what get noticed and affect behavior are the peculiar (unpredictable, information-rich) aspects of stimuli. Social situations are manipulated to vary the extent to which a person's gender, ethnicity, etc., is distinctive from that of other group members and so becomes salient in perception and determining of behavior. Contexts of other social stimuli (jobs, institutions, etc.) are manipulated to vary the distinctiveness of their assets and shortcomings, allowing tests of predicted changes in perception, liking and behavior regarding them. A second line of work on content and structure of thought uses elaborate content analysis systems to test predictions regarding: shifting patterns of verb use as children grow older, differences between self- and other-perceptions, how affirmation ("Tell us about yourself") self-concepts differ from negation ("Tell us what you are not") self-concepts, differences between verbal and pictorial expressions of thought, and the sequence of thought during continuous verbalizing. A theory of the content, structure, and functioning of belief systems is used in a third series of studies, first to elicit the network of thoughts surrounding a given issue (e.g., the perceived antecedents and consequences of donating blood) and then to trace how introducing new information specific to the central (blood-donating) issue has remote asymmetrical and delayed impacts on other, unmentioned beliefs in the system. A fourth line of research tests how independent variables such as phonological ease, cognitive availability, psychodynamic involvement, etc., determine "arbitrary" word-order regularities (e.g., saying "needle and thread" rather than "thread and needle"). Writing reviews that apply research on the above topics to basic theory and to public health practice is a fifth line of work. A sixth undertaking is to develop an archive of historical data relevant to social science theorizing about how social situations and personal predispositions interact as both causes and effects of historical fluctuations in public health, scientific and technological advances, social conflict, etc. Conceptual and methodological interrelations among the six lines are described.